1. Field of the Invention
The invention relates to ascertaining properties of a material using entangled photons. In particular, the invention relates to directing entangled photons to a material, possibly located at a distance from the source of entangled photons, in order to ascertain properties of the material by detecting evidence of entangled photon absorption by the material.
2. Discussion of Background Information
Photons are quanta of electromagnetic energy. Multiple photons may be entangled or not entangled. Photons that are not entangled together (i.e., random photons) exist as independent entities. In contrast, entangled photons have a connection between their respective properties.
Two photons entangled together are referred to as an entangled-photon pair (also, “biphotons”). Traditionally, photons comprising an entangled-photon pair are called “signal” and “idler” photons. Measuring properties of one photon of an entangled-photon pair determines results of measurements of corresponding properties of the other photon, even if the two entangled photons are separated by a distance. As understood by those of ordinary skill in the art and by way of non-limiting example, the quantum mechanical state of an entangled-photon pair cannot be factored into a product of two individual quantum states.
In general, more than two photons may be entangled together. More than two photons entangled together are referred to as “multiply-entangled” photons. Measuring properties of one or more photons in a set of multiply-entangled photons restricts properties of the rest of the photons in the set by constraining measurement outcomes. As understood by those of ordinary skill in the art and by way of non-limiting example, the quantum mechanical state of a set of n>2 multiply-entangled photons cannot be factored into a product of n separate states. The term “entangled photons” refers to both biphotons and multiply-entangled photons.
General techniques for ascertaining spectroscopic properties of materials are known. Such techniques typically rely on directing non-entangled (random) photons at a material, which absorbs the photons and emits fluorescence. In general, these techniques rely on varying the frequency of the non-entangled photons. By comparing incident photon energy with the energy of resulting fluorophotons, the absorbing material may be crudely characterized.